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G. F. KRETZ. nnEnGlNG MACHINE.

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No. 6I6,675. Patented D ec. 27, i898. G. F. KRETZ.

DREDGING MACHINE.

(Application led Nov. 30, 1896.)

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ArnNr DREDGING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 616,675, dated December 27, 1898. Application tiled November 30, 1896. Serial No. 613,905. (No model.)

To @ZZ whom, it ntay concern:

Be it known that I, GEORG FRANZ Knnrz, engineer, a subject of the Emperor of Germany, residing at Carlsruhe, in the Grand Duchy of Baden, Germany, have invented certain new and useful Improvements in Dredging-Machines; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Sheet l, Figure l: The left side of this iigure shows a ground plan of the dredging-machine lixed on the outside of the boat, Jthe right side the same in longitudinal section, and c denotes the hydraulic reservoirs for the water used in this performance of the patent, which are attached at each side of the boat and can be 'fixed at any required depth for dredging. Fig. 2 shows a side view of this scouring-dredger,with the jet-nozzles d, sliding and elevating mechanism e, which enables the position of the machine to be varied, and the apparatus for preventing fallingin of debris, consisting of the guard-plates 7.3. Fig. 3 represents a cross-section of the hydraulic reservoirs c while at work and shows the spoil-channel, with stuit dredged, (sand, mud, graveh) formed by the action of the water-j et d; further, the guard-plate 7.',which prevents materials loosened by such action of the water-jet from falling into the dredged channel. Fig. is a horizontal section through Im n of Fig. 3 through the hydraulic reservoir, which is here shown on a larger scale than in Fig. l, also through the movable tongues fand the sliding and elevating mechanism e. Sheet 2: Fig. 5 gives a detailed view of the throttle-valves 7l in cross-section, these also appearing in Fig. l. As well are shown in relativelyY appropriate size and direction the movable tongues f. Fig. 15 represents a longitudinal section at C D of Fig. 5, with the movable tongues f in various positions, sundry sections of the nozzles d, as well through the throttle-valves t. Fig. 7 is a vertical section through the hydraulic reservoir c, from which can be seen the regulating contrivance of the nozzles-a rail which,

high water and moved by screws, gears rack or tooth like into the tongues of the nozzles.

The machine constructed as the subject of my invention has for its object the removal from the channel of navigable rivers of the deposit, silt, or Shoal-bank left after each to place it right and left in the unused parts of the river-bed. To attain this end, two hydraulic reservoirs c, occupying the required width of the channel, are fixed to or built in the bow of one or more vessels or boats coupled together, in which are the necessary machines, pumps, screws, and other appliances for the production of water-jets, and moved upstream with such vessels and pressed upon the Shoal-bank. Along the whole length of the hydraulic reservoir c, beneath, there is a complete system of nozzles for water-j ets d, arranged side by side at small intervals.

The j et-nozzles d, with the hydraulic reservoirs, are variable vertically by the sliding and elevating mechanism e, and their direction in a horizontal plane can be changed through movable tongues f. The first arrangement provides for getting properly at the different dredging depths, the second for giving such a direction to the watenjets as suits the demolishing operations needed for loosening the stuff to be dredged. The direction of the jets is in every single case so to be selected that the force of the jets not only Compasses the loosening of the Shoals, but as well shifts away the loosened material out of the channel.

By means of pumps and other suction and pressure apparatus on or in the dredgingboat, from this scouring-dredger, through the nozzles on the hydraulic reservoir c, at the dredging depth, Figs. l and 3, powerful jets of water are ejected againstthe bottom or foot of the Shoal-bank. In this way the latter is undermined along the entire line of attack of the jets of water, and thus between the Shoal-bank and the hydraulic reservoir an almost completely-blocked trough or spoilchannel is formed, in which the loosened stuff played upon by the action of the jets is swept out of the channel.

consecutive As the work of breaking down the shoal-bank progresses the vessel equipped with the scoiuing-dredger is moved upstream and continually kept in contact With the surfaces of the Shoal-bank to be operated upon.

In case the stuff being dredged yields unequally to treatment throttle-valves z' make an appropriately diminished or increased pressure possible Awith separate portions of thejets, While the guard-plates 7,3, Figs. 2 and 3, and the scraper Z, Fig. 3, prevent the falling of Waste and pebbles into the cleansed channel.

The contrivances hitherto known as jetdredgers77 only aim at stirring or furrowing up muddy bottoms and then leaving everything further to the current. Removal of the Shoal stuff by Water-jets is not provided for by them.

The dredging apparatus can be placed,

either movable or stationary, on the motorboat or can also be .built in the boat itselff and can be Worked hydraulically or with compressed ai r.

That I claim as myinvention, and desire to secure by Letters Patent, is-

Scouring-dred ger specially recognizable by two hydraulic reservoirs c occupying the de? GEORG FRANZ KRETZ.

lVitnesses:

FRIEDRICH SISBAUER, FRED HOFMANN. 

